Electric switch



Sept. 15, 1942. A. w. KRIEGER 2,295,

ELECTRIC SWITCH Filed March 27, 1941 3 Sheets-Sheet l INSULATION Sept.15, 1942. A. w. KRIEGER 2,295,668

ELECTRIC SWITCH Filed March 27, 1941 3 Sheets-Sheet 2 Sept. 15, 1942. A.w. KRIEGER 29 ELECTRIC SWITCH Filed March 2'7, 1941. s Sheets-Sheet 5 m12 v J 5a 55 55 5a 55 5a 54 5/ (III II VIII/III Patented Sept. 15, 1942ELECTRIC SWITCH Alvin W. Krieger, Milwaukee, Wis., assignor toCutler-Hammer, Inc., Milwaukee, Wis., a corporation of DelawareApplication March 27, 1941, Serial No. 385,398

23 Claims.

This invention relates to improvements in electric switches, and theinvention relates more particularly to improvements in switches adaptedto control alternating current circuits.

A primary object of the invention is to improve and simplify the detailsof construction and assembly of the parts and the operation of switchesof the aforementioned character.

Another object is to provide for utilization of a minimum number ofdifferent switch parts in the construction of switches having difierentoperative characteristics, different types of wiring terminal elements,and diiierent types of mounting and operating elements for the switchesas a whole.

Another and more specific object is to provide an arrangement whereinthe recessed insulating base, the insulating cover member therefore, thespring biased contactors, and the insulating actuating elementsassociated with the latter, are

common to all of the various forms of switches herein contemplated.

Another object is to provide a novel form of single-pole, four-breakswitch adapted for control of an alternating current circuit,

Another object is to provide novel units of superstructure, includingmanual operating levers, to be alternatively and selectively associatedwith the insulating base and the parts carried by the latter.

Another object is to provide a novel ganging arrangement of a pluralityof double-pole, alternating current controlling, switches of theaforementioned characterto function as a single switch for the controlof four, six, or more, poles of an alternating current circuit.

Another object is to provide novel forms of combined contact and wiringterminal members and contactors for switches of the aforementionedcharacter.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of theinvention which will now be described, it being understood that theembodiments illustrated are susceptible of modification in respect ofcertain structural details thereof without departing from my inventionas defined by the appended claims.

In the drawings,

Figure 1 is a top plan view (slightly over twice normal scale) of therecessed molded insulating base, which is common to all of the variousswitches herein disc1osedone longitudinally members being shown inposition-it being understood that in practice the bridging contactorsand their biasing springs will first be positioned in the base recess.

Fig. 2 is a. sectional view, on the line 2-2 of Fig. 1, showing thecompletely assembled parts of a double pole, single throw, momentarycontact, binding screw terminal type of switch, the same having asuperstructure adapted to provide for two-screw mounting of the completeswitch within a tool handle or other suitable support (not shown)theswitch parts being shown in 01f position.

Fig. 3 is a sectional view, on the line 3-3 of Fig. 1, of a completeswitch having a supporting and operating superstructure like that ofFig. 2, with the switch parts in off position.

Fig. 4 is an enlarged sectional view taken transversely, on the line 44,of Fig. 2-the switch parts being in off position.

Fig. 5 is a perspective view, in separated relation of certain of theswitch parts shown in Figs. 1 to 4.

Fig. 6 is a view similar to Fig. 1, but illustrating a modifiedarrangement of stationary contacts to provide a single-pole switch ofthe fourbreak typethe bridging contactors and their biasing springsbeing omitted for clarity of illustration.

Fig. 7 is a perspective view of the connector which forms two of thestationary contacts in the switch of Fig, 6.

Fig. 8 is a perspective view of a solder-lug type of combined wiringterminal and contact member which may be substituted for thecorresponding elements of Figs. 1 to 6.

Fig. 9 is a perspective view of a wire-lead type of combined stationarycontact and terminal member which may be substituted for any of thecorresponding elements of the other figures.

Fig. 10 is a sectional view of a double pole, single throw, switchsimilar to Fig. 2, but showing a one-hole mounting type ofsuperstructure and operating lever, with the switch parts in onposition; certain of the parts being shown in elevation.

Fig. 11 is a sectional view, on the line ll-|l of Fig. 10the switchparts being in on position.

Fig. 12 is a view, partly in end elevation and partly in verticalsection, of a six pole, single throw switchthe same comprising unitarysupporting and operating means for three double pole switches of thecharacter illustrated in alined pair of combined contact and terminalFigs. 1 t0 5.

Fig. 13 is a fragmentary sectional view, on the line l3l3 of Fig. 12.

Fig. 14 is a fragmentary sectional view, on the line '.l4 of Fig. 12.

Fig. 15 is a fragmentary vertical sectional view of a momentary contacttype of switch similar to that of Figs. 2 to 4, but having a modifiedform of supporting superstructure and operating lever.

Fig. 16 is a fragmentary sectional view, on the line i6l6 of Fig. 15.

Referring to the switch shown in Figs. 1 to 5, the numeral 26 designatesan insulating base of substantially rectangular contour molded from anysuitable insulating material-preferably Bakelite. Base 20 is providedwith a group of three transversely alined, longitudinally parallelrecesses 2|, 22 and 23. The opposite end recesses 22 and 23 are of likeform, and as best illustrated in Fig. 3 each is of substantiallyinverted, stepped, pyramidal form in vertical cross section. The lowerend portions 22 and 23 of said end recesses are of substantiallycylindrical form, against the bottom Walls of which a pair of likesprings 24, 24 (Figs. 3 and 4) are adapted to seat. The relativelylarger intermediate portions 22. and 23 of said recesses are ofsubstantially rectangular contour (Figs. 1, 3 and 4); and the largest orupper end portions 22 and 23 are likewise of rectangular contour, but ofgreater dimensions, longitudinally of base 23, than the portions 22 and23 The central recess 2| includes a lower end portion 21 ofsubstantially cylindrical formthe portion 2i being of the same height asbut of greater diameter than the portions aforedescribedsee Fig. 4. Acoiled compression spring 25 of greater size and strength than thesprings 24, 24, is adapted to seat against the bottom wall of portion ZiThe upper end portion 21 of recess 2! is of substantially rectangularcontour and of greater size, longitudinally of base 23, than the endrecesses 22 and 23. The end wall 2 i of portion 2| is cut away, as shownat 2| in Figs. 1 and 2, to accommodate one end of a molded insulatingcam member 26said end of the cam member having alined cylindrical pivotlugs 2E and 25 formed integrally therewith and extending from opposite sdes thereof (Fig. 5); the side walls of portion Zi of recess 2! beingrespectively provided with upwardly opening substantially rectangularrecesses 2i and 2 i to respectively accommodate lugs 25 and 2G. in aposition only slightly below the upper surface of base 2G-thus providingfor oscillatable support of said cam member.

A pair of like substantially U-shaped bridging contactors 21, 2'1 areloosely positioned within the portions 22 and 23 the form of saidcontactors being best illustrated in Figs. 3 and 5. The substantiallyfiat connecting portions 2l of said contactors are respectively adaptedto seat against the upper ends of springs 24, 24the latter acting at alltimes to move said contactors toward the upper extreme position thereof.As indicated in Figs. 1 and 3. the lower ends and arm portions ofcontactors 2! are adapted for a free sliding fit within the portions 22and 23 of the recessesthe side and end walls of said portions of therecesses assisting restricting the contactors to straight-linereciprocating movements.

The upper ends of the arms of said contactors 21 are bent to extendoutwardly and downwardly in arcuate form, as shown at 27 and 27 in Figs.

2 and 23 3 and 5the purpose of the curved tips of the contactor armsbeing to reduce the likelihood of deposition of dust particles or otherforeign substance upon said tips, and to overcome the disadvantageouseffect of the presence of such foreign particles if deposited thereon-itbeing noted (see Fig. 3) that said contactors are self-adjusting to alimited extent to compensate for any possible irregularities in thesurfaces of said tips.

The walls between the central recess 21 and end recesses 22 and 23 areprovided with notches 28 and 29 and the outer side walls of recesses 22and 23 are respectively provided with vertical grooves 38 and 3isaidnotches and grooves being alined with each other and with the centerlines of recess portions 21 21.. an (Fig. 1) and preferably extending tothe plane of the bottom walls of recess portions 2i 22F and 23 as shownin Fig. 4. A fiat, punched insulating plate 32 is positioned edgewisefor vertical reciprocation within said notches and grooves, as shown inFig. 4. A lower edge portion 32 of plate 32 is adapted to seat againstthe end of spring 25spring 25 being at all times under compression,whereby plate 32 is normally biased toward its upper extreme position.

Plate 32 is preferably provided at the center of its lower edge with anintegral extension or lug 32 which fits into the upper end of spring 25to assist in retaining said parts in proper relationship to each other.The opposite end portions 32 and 32 of plate 32 are respectivelypositioned between the arms of contactors 21, 2'!- the lower edges ofsaid plate portions overlying the connecting portions of saidcontactors, whereby upon depression of plate 32 to its lower extremeposition the contactors 21, 21 will be depressed to their lower extremepositions against the bias of springs 24, 24 (see Figs. 3 and 4) forinterruption of the controlled circuit. Plate 32 is preferably providedin its upper edge with a notch 32 which is adapted to accommodate thefree end portion of cam member 23 to assist in restricting said plate toreciprocating movement in a straight line.

As shown at the lower end of Fig. 1, base 20 is provided with sets ofledge portions-the ledge portions of each set being respectivelydesignated by the numerals 25 25*, 23 22V and 25 Said ledges are locatedin a common plane oifset downwardly from the upper surface of base 23 toan extent substantially corresponding to the thickness of the horizontalfiat portions 33 of four like combined contact and wiring terminalmembers 33 formed of sheet metal. Portions 33 are provided on oppositesides thereof with alined rectangular notches 33 and 33 (Fig. 5), eitherof which notches is adapted to accommodate one of the four portions 21"formed integrally with the upper surface of the base-depending uponright-hand or left-hand mounting of said members at the respective endsof the base.

The wiring terminal portion 33 of each member 33 is formed integrallywith and bent downwardly at substantially a right angle to the flatportion 33 thereof-said terminal portion having an inwardly extruded andtapped opening 33 formed therein to accommodate the shank of a bindingscrew 33 of usual form. As best illustrated in Figs. 1 and 3, base 26 isprovided with four recesses 20 to accommodate the shanks of screws 33each of said recesses opening to the upper surface and to one of the endsurfaces of said base. The head 33 of each fiat portion 33 preferablyhas rigidly attached to its lower surface a substantially circular diskor plate 33 of silver or a silver alloy. In this connection attention iscalled to the fact that the contactors 21 are preferably formed ofbimetallic strips composed of an inner layer of a noble metal, such assilver or a silver alloy, and an outer layer of a base metal, such asbrass; said strips when bent to form the contactors 21 providing forexposure of the layer of silver or silver alloy at the upper surfaces ofthe respective tips 21' and 21 of the contactors. By providing tipscomposed of such material upon the contacts and contactors the currentcontrolling capacity and the life of the switches is greatly increasedascompared with similar switches having tips formed of a base metal.

In order to minimize the amount of molding material required forproduction of base -whi1e providin the required depth of the recessportions 21 2? and 23 I prefer to provide upon the lower surface of thebase a transversely extending substantially rectangular downwardextension 26 I prefer to provide at opposite ends of the base therelatively thin extensions 20 and 20 (Figs. 1 to 3) which act asinsulating barriers between the end pairs of binding screws 33 and thecircuit wire ends to be clamped thereby.

As best illustrated in Fig. l, the combined contact and terminal membershave their flat portions 33 positioned ina substantially flushrelationship to the upper surface of the base and in a relation toprevent transverse displacement of the former with respect to the latterin any direction. All of the aforedescribed parts are held in properlyassembled relationship to base 20 by a flat, punched insulating plate 34of rectangular contour,the width of said plate prefer ably correspondingwith that of the base, and the length of said plate being coextensivewith the outer ends of barriers Ml and 20 as shown in Figs. 2 and 3.Plate 34 is rigidly secured to the upper surface of base 20 as by meansof a pair of screws 35, (Fig. 3), the shank ends of which take intotapped openings in a metal plate 36, hereinafter more fully described.Plate 34 is provided with a centrally located rectangular slot 34 of alength and width to afford oscillatory clearance for cam member 26 andfor the lower end extension 3'1 of a pivoted manual operating lever 31(see Figs. 2 and 4; and Figs. 10 and 11 wherein a different type oflever is employed). As will be noted in Fig. 2, plate 34 overlies thecam lugs 26 and M5 whereby the latter are positively retained within theaforementioned bearing recesses. Plate 34 is also provided withclearance openings for the shanks of screws 35.

Metal plate 36 is provided with a centrally located substantiallyrectangular opening 36 which is relatively wider and longer than theopening 3t aforedescribed. Plate 36 is provided at opposite sides of oneend of opening 36 with a pair of lugs partially sheared therefrom andbent upwardly at a predetermined angle thereto as shown at 35* and 36 inFig. 4, for a purpose to be described. Positioned upon the upper surfaceof plate 36 is a drawn or stamped sheet metal housing member 38 ofsubstantially rectangular contour. The length of the hollow portion ofmember 38 substantially corresponds with the length of plate 36-andmember 38 is provided on opposite sides thereof with longitudinallyextending horizontal flanges 38 and 38, each of which flanges is rigidlyattached to plate 36 at two or more longitudinally spaced points, as byspot welding.

Prior to thus rigidly and permanently uniting housing 38 to plate 36,the reduced upper end portion 31 of lever 31 (prior to attachment ofknob 31 thereto with a drive fit) is passed upwardly through the slot 38in the upper end of housing 38-said slot providing oscillatory clearancefor the lever and being at all times substantially closed by one or theother of the arcuate enlargements 3'! or 31 of the lever. Projectingbeyond the respective enlargements 31 and 3'!" at predetermined anglesthereto are lugs 3T and 31 the upper edges of which are adapted toengage the inner surface of the upper end wall of housing 38 to limitthe throw of lever 31 to insure a like angular extreme position thereofin each direction.

In order to effect automatic return of lever 31 to its right-handextreme position (Fig. 2 and 3) upon manual release thereof, I provide acoiled torsion spring 39 having a connecting portion 39 which is engagedwith the lower edge of lug 38 portions 39 and 39 coiled in a likedirection outwardly from said connecting portion, and parallel straightend portions 39 and 39 which are adapted for engagement, with apredetermined degree of pressure, against the upper surface of metalplate 36. End portions 39 and 39 are restrained by the respective lugs36 and 36 against inward displacement relatively to each other.

Lever 3! is provided with an opening 3'! to accommodate a drive fit theintermediate enlarged portion 40 of a pin 40--the side walls of housin38 having relatively larger alined openings 38 and 38 (Fig. 4) to freelyreceive the pin 40 inclusive of its enlarged portion 40 when insertedfrom either side of said housing. Lever 31, spring 39 and pin 40 willthus be retained in assembled relation to housing 38,the metal plate 36when welded to the housing engaging the spring ends 39 and 39 to apply apredeterminad degree of torsion strain to the spring. The knob 31 isapplied with a drive fit to the reduced end 31 of the lever after upwardinsertion of the latter through said slot 38. Housing 38 is providedwith a pair of spaced tapped openings 38 and 38 to accommodate theshanks of screws (not shown) for attaching the switch to a tool handleor other suitable housing or support. The switch of Figs. 1 to 5-has arated capacity of 10 amperes at 250 volts, alternating current.

In the modified form of switch illustrated in Figs. 6 and '7 it is to beunderstood that the various parts thereof may be identical with thoseillustrated in Figs. 1 to 5, except that the two combined contact andwiring terminal elements at the left hand end of the switch (Figs. 1 to3) will be omitted; and in their stead a punched sheet metal bus memberil will be employed-- base 20 being provided with a transverse groove orrecess 28 (Figs. 1 and 6) to accommodate the mid-portion ii of said busmember, whereby the latter is seated in a substantially flush relationto the upper surface of said base. Bus mem ber 4| is so shaped withrespect to the recesses and shoulders formed in the upper surface ofbase 20 as to prevent substantial lateral displacement of the formerwith respect to the latter. The stationary contact portions M and 4l ofthe bus member have spot welded to the under surfaces thereof the silveror silver alloy contact tips 4! corresponding to the tips 33aforementioned. With an arrangement like that shown in Fig. 6 thecircuit to be controlled by the switch will be made or broken at fourpoints, as will be obvious. As will be understood, the contactors andtheir associated elements, as well as the operating superstructure, areomitted for clarity of illustration-it being understood that the otherswitch parts not shown may be identical in size and shape with those ofFigs. 1 to 5. The form of the bus member 4|, with its attached contacttips 4 I is shown in perspective in Fig. 7.

Fig. 8 shows in perspective a modified form of combined stationarycontact and terminal member 42 whicn may be substituted for the members'33 in any of the switches herein disclosed. The flat portion 32 ofmember .2 corresponds in shape with the fiat portion 33 of member 33aforedeecribed,the contact head portion 42 having the silver or silveralloy tip 42 spot welded to its lower surface, as aforedescribed. Thewiring terminal portion 42' is bent downwardly at a predetermined angleto fiat portion 42 said portion 42 having a punched opening 42 thereinto provide insertion or looping of a wire end therethrough and solde;Jig of the same thereto.

The alternative form of combined contact and wiring terminal membershown in perspective in 9 is adapted to provide for concealed wiring ofthe switcha desired length of wire 44 having its bared end 44 insertedupwardly through an opening 43 and then bent fiatwise against the fiatterminal portion 43 to which it is attached, as by spot welding. Portion43 is ofiset downwardly from and in a plane parallel to the relativelyshort flat portion 43 of member 43the contact head portion 33 of thelatter having a silver or silver alloy tip 43 spot welded to its lowersurface. The wire end 44 is thus attached to member 53 prior to assemblyof the switch parts, and the point of attachment is concealed within thebody of the switch, leaving exposed a length of the wire (such as fiveor six inches) whose bared outer may be attached to a circuit Wire bysolder or in any other us al manner.

The switch illustrated in Figs. 10 and 11 may be identical with that ofl to 5 in respect of the insulating plate 34 and all of the partspositioned therebelow. is of the one-hole mounting type, and according-1y I provide a punched and stamped sheet metal top plate 45, thecentrally located bulged portion of which is provided with an opening toreceive the reduced lower end 4 3 o an externally threaded hollow metalbushing 45, said end 45 being upset over the lower surface of portion413 to rigidly and permanently secure said parts to each other. Bushing45 is provided with an upper end opening 45* of reduced diametertheopening 45' being sufiiciently large to provide for upward passagetherethrough of the substantially spherical knob 42' forming an integralpart of the machined lever 47. The intermediate enlarged portion 41 ofsaid lever is adapted to substantially close said opening 45', in theassembled relation of the parts, while providing for oscillatorymovement of the lever with respec thereto.

The enlarged portion 4?) of said lever is provided, by drilling, with atransverse passage 41 which is adapted to accommodate with a drive fitthe flattened or otherwise enlarged intermediate portion 48 of anotherwise substantially The switch of Figs. 10 and 11 cylindrical pin48; bushing being provided with alined drilled openings 46 and 45 toprovide for insertion of said pin transversely in either direction tothe position thereof shown in Fig. 1l-said openings acting as bearingsfor the opposite ends of said pin. Lever 41 is provided at its lower endwith an integral cylindrical stud or projection 4? of reduceddiametersaid projection preferably having a substantially hemisphericalend 47 for cooperative engagement with the cam member 25 aforedescribed.As will be understood, a pair of nuts (not shown) are preferablyassociated with bushing 45 to provide for adjustable support of theswitch within a hollow tool handle or other suitable support having asingle circular opening to accommodate said bushing,

In the six-pole, single throw switch of Figs. 12, 13 and 14 I employthree double-pole, single throw switches which are identical, up to theinsulating plates 34, with the switches of Figs. 1 to 5, 10 and 11asindicated by the corresponding numerals of reference. In Figs. 12 to 14,however, the three switch bases 20 with their associated parts are eachattached by a pair of screws 49 (Fig. 13) to a metal top plate 50forming a part of the supporting and operating superstructure.Superimposed upon plate 50 is an inverted shallow, cup-shaped housingmember 5| of substantially rectangular contour. Housing 5| is preferablyprovided at at least one point along each end wall (Fig. 12) and at atleast two points along each side wall (see Fig. 13) with vertical lugsor extensions 5W which are freely insertable into correspondinglypositioned downwardly flared openings 50 (Figs. 12 and 13)- said lugsafter insertion being upset as illustrated to rigidly and permanentlysecure said parts in assembled relation.

Prior to such assembly there is positioned within housing member 5| ametal rod 52, shown as of circular cross section, onto which rod areslidably fitted a pair of levers 53, 53 having downward projections 5353 for cooperative engagement with the cam members 26 of the respectiveend switch parts, and an intermediate lever 54 having a downwardprojection 54 for cooperation with the cam member of the intermediateswitch parts. Levers 53, 53 and lever 54 are secured to rod 52, withtheir projections 53, 53 and 54 arranged in a like angular position, asby spot welding or brazing at points 53 53 and 54', 54, respectively, topositively restrain said levers against endwise or rotary displacementwith respect to said rod.

Housing 5| is provided in its upper end wall with a slot 5| (Figs, 12and 14) to provide for upward insertion of lever 54 (Fig. 12) prior toattachment of knob 54 with a drive fit to the reduced upper end of saidlever--said slot affording oscillatory clearance for lever 54, asindicated by the dotted lines in Fig. 14. Rod 52 is provided in itsopposite ends with drilled recesses 52 and 52 (Fig. 12) to receive witha drive fit the pins 55, 55which are inserted thereinto through openings5| c and 5| in the respective end walls of the housingsaid openingsproviding bearings for said pins to provide for oscillatory movement ofsaid rod and the levers attached thereto. Housing 5! may be provided inits upper end wall with a pair of suitably spaced tapped openings (notshown) to provide for attachment of the switch unit to a panel or othersuitable support.

Although I have shown a six-pole switch mechanism, it is to beunderstood that the number of poles to be operated may be increased ordecreased by increasing or decreasing the number of switch bases 20employed, with corresponding changes in the length and arrangement ofthe parts of the superstructure.

As will .be noted, the metal plate 50 is provided with a centrallylocated elongated rectangular opening 58 of a width substantiallycorresponding to the width of the slots 34*- in insulating plates 34.Two insulating plates 55 having head portions 56 of greater width thanslot 50 and neck portions 56 of a width only slightly less than saidslot 58 are assembled by insertion of the plate heads upwardly throughslot 50* longitudinally of the lattersaid plates being then turned tothe positions thereof illustrated to restrain the same against downwardor upward displacement. As shown in Fig. 14 plates 56 are of a lengthcorresponding to the length of bases 20-whereby said plates whenpositioned between the adjacent bases 28 act to properly insulate fromeach other the adjacent wiring terminal screws 33 and the circuit wireends to be attached thereto.

The trigger-lever operated form of momentary-contact type of switchillustrated in Figs.

15 and 16 is generally quite similar to that of Figs. 1 to 5, anddiffers therefrom primarily in respect to the elements of the supportingand operating superstructure. In the switch of Figs. 15 and 16 I preferto employ two insulating top plates 34, 34, with corresponding longerscrews 35 35 which take into tapped openings in the metal top plate 51.Plate 51 is of substantially rectangular contourthe same having anopening 5'! formed therein to provide clearance for the substantiallycircular lower end portion 58 of a lever 58 and for the lower endportion 59 of a flat, punched insulating plate 59 whose upper edgeportion fits within a rectangualr radial notch 58 formed at apredetermined point in the periphery of portion 58*.

Plate 51 is provided with four perforated upwardly projecting bosses 5lthe openings in saidbosses being adapted to receive downward- 1yextending lugs formed integrally with the lower edges of the side walls80 and 68 of an inverted, channel-shaped sheet metal member 60 the lowerends of said lugs being upset against the lower surfaces of the bosses,as indicated in dotted lines in Fig. 16. Member 68 is provided in itsupper end wall with a substantially rectangular opening 68 extendingthroughout the width of said wall, to provide oscillating clearance forthe portion 58 of lever 58. Two pairs of lugs are formed integrally withsaid wall and are bent downwardly through opening 60 for positioning ofthe lugs of each pair on opposite sides of portion 58= one lug of eachpair being shown at E8 and SN in Fig. 15. The purpose of said lugs is torestrict lever 58 to oscillatory movement in a single plane.

A return spring of the torsion type has its connecting portion 64*engaged with lever 58 as illustrated to bias the same to move in acounterclockwise direction (Fig. 15), the portions Gl and 6 l of saidspring being coiled in a like direction for location thereof on oppositesides of lever 58, and the straight end portions Bl and til of saidspring being adapted to engage the upper surface of plate 51 with apredetermined normal degree of pressure, which is increased uponclockwise rotation of the lever 58. A

headed pin 62 penetrates alined openings in the side walls 60 and 68 ofmember and in the center of lever portion 58 --the shank end 62" (Fig.16) of said pin being upset or flattened as shown to retain the same inassembled position.

Portion 58 of lever 58 is provided at a predetermined point in itsperiphery with an integral lug or extension 58 which is engageable withthe upper surface of plate 51 and with the lower surface of theaforementioned wall 68 to limit the rotary movement of lever 58 in eachdirection. The upper end of lever 58 has an angled edge portion 58 towhich the inverted, channelshaped trigger or finger grip 63 is rigidlyattached at the two points of contact of said parts, as by spotwelding-it being noted that the upper surface of member 63 is preferablyof curved form, as illustrated. The end wall 60 of member 60 is providedwith a pair of spaced tapped openings 60 and 68 to provide for concealedmounting of the switch unit Within a tool handle or the like, as bymeans of a pair of securing screws.

With reference to the switch of Figs. 1 to 5, it Will be apparent tothose skilled in the art that spring 39 may be omitted, if desired; thusproviding a switch which is functionally and operatively similar to thatillustrated in Figs. 10 and 11.

I claim:

1. In an electric switch of the slow break type, in combination, amolded insulating base having a recess formed therein and opening to theupper surface thereof, substantially U-shaped contactors positionedwithin said recess, coiled compression springs interposed between thebottom wall of said recess and the connecting portions of the contactorsrespectively positioned therewithin whereby said contactors are normallybiased toward their upper extreme positions, a flat plate of insulatingmaterial reciprocable vertically within said recess, said plate beingpositioned between the arms of said contactors and adapted to seatagainst the connecting portions of the latter, a cam member looselypivoted within said recess and having a lower edge portion engaged withthe upper edge portion of said plate, said cam member being pivotallymovable downwardly within said recess to provide for depression of saidplate and said contactors against the bias of said springs, stationarycontacts positioned within said recess for engagement by the respectivecontactors in the upper extreme positions of the latter, said contactshaving portions loosely seated upon the upper surface of said base in arelation to prevent lateral displacement with respect thereto, and aninsulating member engaging the upper surface of said base to retain allof the aforementioned parts in assembled relation.

2. In an electric switch of the slow break type, in combination, amolded insulating base having a recess formed therein and opening to theupper surface thereof, substantially U-shaped contactors positionedwithin said recess, coiled compression springs interposed between thebottom wall of said recess and the connecting portions of the contactorsrespectively positioned therewithin, whereby said contactors arenormally biased toward their upper extreme positions, a fiat plate ofinsulating material reciprocable vertically within said recess, saidplate being positioned between the arms of said contactors and adaptedto seat against the connecting portions of the latter, a cam memberloosely pivoted within said recess and having a lower edge portionengaged with the upper edge portion of said plate, said cam member beingpivotally movable downwardly within said recess to provide fordepression of said plate and said contactors against the bias of saidsprings, stationary contacts positioned within said recess forengagement by the respective contactors in the upper extreme positionsof the latter, said contacts having portions loosely seated upon theupper surface of said base in a relation to prevent lateral displacementwith respect thereto, an insulating member engaging the upper surface ofsaid base to retain all of the aforementioned parts in assembledrelation, said insulating member having an opening formed therein toprovide oscillatable clearance for said cam member, and a manuallyoperable member supported above said base and movable between oppositeextreme positions to effect corresponding movements of said cam member,said manually operable member having a portion extending downwardly intosaid last mentioned opening in all positions of the former.

3. In an electric switch of the slow break type, in combination, aninsulating base having a recess opening to the upper surface thereof,said base having downwardly offset ledges formed thereon, a pair ofstationary contact members having fiat portions thereof seated upon saidledges in a substantially flush relationship to the upper surface ofsaid base, said flat portions having notches and said base havingintegral lugs cooperating therewith to prevent substantial lateraldisplacement of said members relatively to said base, said membersrespectively having tips overlying the upper end of said recess inspaced relationship to each other longitudinally of said base, asubstantially U-shaped contactor positioned Within said recess, a coiledcompression spring interposed between the bottom wall of said recess andsaid contactor to normally bias the latter into bridging engagement withsaid contact tips, a fiat, punched insulating plate positioned edgewisewithin said recess and having a portion overlying the connecting portionof said U, and an insulating cam member oscillatably supported by saidbase and overlying the upper edge of said plate, said cam member beingoscillatable at will to effect depression of said plate and saidcontactor against the bias of said spring.

4. In an electric switch of the slow break type, in combination, aninsulating base having a recess opening to the upper surface thereof,said base having downwardly offset ledges formed thereon, a pair ofstationary contact members having fiat portions thereof seated upon saidledges in a substantially flush relationship to the upper surface ofsaid base, said flat portions having notches and said base havingintegral lugs cooperating therewith to prevent substantial lateraldisplacement of said members relatively to said base, said membersrespectively having tips overlying the upper end of said recess inspaced relationship to each other longitudinally of said base, asubstantially U-shaped contactor positioned within said recess, a coiledcompression spring interposed between the bottom wall of said recess andsaid contactor to normally bias the latter into bridging engagement withsaid contact tips, a flat, punched insulating plate positioned edgewisewithin said recess and having a portion overlying the connecting portionof said U, spring means normally acting to bias said plate upwardly outof engagement with the connecting portion of said U whereby said firstmentioned spring is relieved of the weight of said plate, an insulatingcam member oscillatably supported by said base and overlying the upperedge of said plate, and a lever pivotally supported above said base,said lever having a lower end portion adapted for continuous cooperativeengagement with said cam.

5. As an article of manufacture, a molded insulating base for anelectric switch of the slow break type, said base having a group ofthree substantially rectangular recesses formed therein and opening tothe upper surface thereof, said recesses being of substantially greaterlength than width and the same being arranged in transversely alinedparallelism between the longitudinal sides of said base, the centralportions of the barriers formed between said recesses being interruptedto provide clearance for a reciprocating actuating element of suitableform, the central recess of said group having a pair of open bearingsformed therein for pivotal support of a cam memberto be associatedtherewith, each of said recesses having a substantially cylindricalcavity formed in its bottom wall to accommodate and to center a coiledcompression spring, the end recesses of said group being adapted toaccommodate reciprocating contactors of suitable form and the centralrecess being adapt-ed to afford clearance for oscillatory movement ofsaid cam member, and said base having in the upper surface thereof aplurality of grooves leading to each of said end recesses to provide forpositioning of a group of stationary contact members in a substantiallyflush relationship to said upper surface of the base.

6. As an article of manufacture, a supporting and operatingsuperstructure for an electric switch of the slow break type, saidsuperstructure comprising a substantially rectangular punched sheetmetal top plate of greater length than width having a pair of tappedopenings formed therein for cooperation with the respective shanks ofsecuring screws whereby an insulating base of suitable form may berigidly attached thereto, said top plate having a relatively largeopening formed therein between said pair of openings aforementioned, apunched and stamped sheet metal member having an area substantiallycoextensive with the area of said plate, said member being of hollowsubstantially rectangular form in longitudinal and transverse crosssection and having longitudinal edge flanges to each of which said plateis spot welded at a plurality of spaced points, said member having apair of tapped openings. and a longitudinally extending slot formed inthe otherwise closed upper end thereof, said tapped openings beingadapted for cooperation with the shanks of screws whereby said membermay be attached to a suitable support, said member having a pair ofalined bearing openings formed in the opposite side walls thereof, aflat, punched sheet metal lever having a relatively large lower end, thereduced upper end of said lever being freely insertable upwardly throughsaid plate opening and said slot whereupon a substantially sphericalknob may be attached thereto with a drive fit, said enlarged lower endof said lever having an opening to be alined with said bearing openings,a pivot pin having an enlarged intermediate portion, said pin beingfreely insertable through said bearing openings and the intermediateportion thereof having a drive fit within said lever opening, wherebysaid lever and said pin are retained in assembled relation to saidmember, said lever having a portion extending downwardly at all timesthrough said plate opening, said plate having a pair of lugs formedintegrally therewith and extending upwardly therefrom at opposite sidesof one end of said plate opening, and a torsion spring having aconnecting portion continuously engaged with the enlarged portion ofsaid lever at one side of said pivot pin, said spring having coiledportions wound in a like direction outwardly from said connectingportion and surrounding said pin on opposite sides of said lever, andsaid spring having straight free end portions continuously engaged undera predetermined degree of pressure with the upper surface of said plate,said free ends of the spring being respectively engaged with said lugsto insure retention of said spring in properly assembled relation.

7. A slow break switch adapted for control of alternating currentcircuits, comprising a molded insulating base having at least threesubstantially rectangular recesses formed therein and opening to theupper surface thereof, the adjacent walls of said recesses havingnotches formed therein and extending throughout the major portion of thedepth thereof, a relatively strong coiled compression spring positionedwithin an intermediate recess and a relatively weak coiled compressionspring positioned within each of the other recesses, a bridgingcontactor positioned within each of the last mentioned recesses andguided by the walls of the latter for reciprocating movement in asubstantially straight line, each of said contactors comprising a sheetmetal strip bent to substantially U-shape, the free ends of the arms ofsaid contactors being bent outwardly at a predetermined angle thereto, afiat punched insulating plate positioned edgewise within said notchesand having portions thereof positioned between the arms of therespective contactors, a molded insulating cam oscillatably supportedwithin said intermediate recess, said cam having a lower edge portionengageable with said plate to eifect downward movement of the latter andsaid contactors against the bias of said springs upon oscillatorymovement of said cam in a downward direction, said springs acting tonormally move said contactors, said plate and said cam toward theirupper extreme positions, a plurality of pairs of contacts overlying therecesses containing said contactors, and a flat I punched insulatingcover plate rigidily secured to the upper surface of said base andadapted to retain all of the aforementioned parts in assembled relation.

8. A slow break switch adapted for control of alternating currentcircuits, comprising a molded insulating base having at least threesubstantially rectangular recesses formed therein and opening to theupper surface thereof, the adjacent walls of said recesses havingnotches formed therein and extending throughout the major portion of thedepth thereof, a relatively strong coiled compression spring positionedwithin an intermediate recess and a relatively weak coiled compressionspring positioned within each of the other recesses, a bridgingcontactor positioned within each of the last mentioned recesses andguided by the walls of the latter for reciprocating movement in asubstantially straight line, each of said contactors comprising a sheetmetal strip bent to substantially U-shape, the free ends of the arms ofsaid contactors being bent outwardly at a predetermined angle thereto, afiat punched insulating plate positioned edgewise within said notchesand having portions thereof 76 positioned between the arms of therespective contactors, a molded insulating cam oscillatably supportedwithin said intermediate recess, said cam having a lower edge portionengageable with said plate to effect downward movement of the latter andsaid contactors against the bias of said springs upon oscillatorymovement of said cam in a downward direction, said spring acting tonormally move said contactors, said plate and said cam toward theirupper extreme positions, a plurality of pairs of contacts overlying therecesses containing said contactors, a flat punched insulating coverplate rigidly secured to the upper surface of said base and adapted toretain all of the aforementioned parts in assembled relation, switchsupporting means also rigidly secured to said base, and movable meanscarried by said last mentioned means for controlling the operation ofsaid cam.

9. A switch adapted for control of alternating current circuits,comprising a molded insulating base having three parallel substantiallyrectangular recesses formed therein and opening to the upper surfacethereof, the adjacent walls of said recesses having notches formedtherein and extending throughout the major portion of the depth thereof,a coiled compression spring positioned within each end recess andadapted to seat upon the bottom wall thereof, a pair of substantiallyU-shaped contactors respectively positioned within said end recesses andadapted to seat against the upper ends of the springs within the latter,a flat insulating plate slidably positioned edgewise within said notchesand extending transversely of all of said recesses, the end portions ofsaid plate being adapted to overlie the connecting portions of therespective U-shaped contactors, a pair of open pivotal bearings formedin the middle recess adjacent one end of the latter, an oscillatableinsulating cam member adapted to overlie the upper edge of said plate atthe mid-portion of the latter, said cam member having laterallyextending lugs positioned within said bearings, two pairs oflongitudinally alined contacts respectively overlying said end recessesfor cooperation with the respective contactors, a flat insulating coverplate overlying the upper end of said base and acting to secure saidcontacts and said cam member in assembled position, and a movableoperating member supported above said insulating cover plate andcooperable with said cam member to effect downward movement of thelatter against the bias of said springs and to permit upward movement ofsaid cam member under the bias of said springs.

10. A switch adapted for control of alternating current circuits,comprising a molded insulating base having three parallel substantiallyrectangular recesses formed therein and opening to the upper surfacethereof, the adjacent walls of said recesses having notches formedtherein and extending throughout the major portion of the depth thereof,a coiled compression spring positioned within each recess and adapted toseat upon the bottom wall thereof, a pair of contactors respectivelypositioned within the end recesses and adapted to seat against the upperends of the springs within the latter, each of said contactorscomprising a sheet metal strip bent flatwise to substantially U-shapewith the free ends of the arms thereof bent laterally with respectthereto, a flat insulating plate slidably positioned edgewise withinsaid notches and extending transversely of all of said recesses, the

lower edge of said plate being adapted to seat at its mid-point againstthe upper end of the middle spring and the end portions of said platebeing adapted to overlie the connecting portions of the respectiveU-shaped contactors, a pair of open pivotal bearings formed in themiddle recess adjacent one end of the latter, an cscillaiable insulatingcam member adapte. to overlie the upper edge of said plate at themid-portion of the latter, said cam member having laterally extendinglugs positioned within said bearings, two pairs of longitudinally alinedcontacts respectively overlying said end recesses for cooperation withthe respective contactors, a flat insulating cover plate overlying theupper end of said base and acting to secure said contacts and said cammember in assembled position, and a movable operating member supportedabove said insulating cover plate and cooperable with said cam member toeffect downward movement of the latter against the bias of said springsand to permit upward movement of said cam member under the bias of saidsprings,

ll. A slow break switch adapted for control of alternating currencircuits, comprising a molded insulating base having at least threesubstantially rectangular recesses formed therein and opehim to theupper surface thereof, the adjacent walls of said recesses havingnotches formed therein and extending throughout the major portion of thedepth thereof, a relatively strong coiled compression spring positionedwithin an intermediate recess and a relatively weak coiled compressionspring positioned within each of the other recesses, a bridgingcontactor positioned Within each of the last mentioned recesses andguided by the walls of the latter for reciprocating movement in asubstantially straight line, each of said contactors comprising abimetallic strip bent to substantially U-shape, the inner surface ofsaid U being composed of metal containing silver and the outer surfacethereof being composed of metal containing copper, the free ends of thearms of said U being bent outwardly and downwardly to substantiallyarcuate form to provide upwardly exposed contactor tips of said metalfirst mentioned, a flat insulating late positioned edgewise within saidnotches and having portions thereof positioned between the arms of therespective contactors, an insulating cam member oscillatably supportedwithin said intermediate recess, said plate having a notch in its upperedge and said cam member being positioned between the side walls of saidnotch and engageable with the bottom wall thereof to effect downwardmovement of said plate and said contactors upon downward oscillatorymovement of said cam member, a plurality of pairs of contact membersoverlying the recesses containing said contactors, each of said contactmembers having a tip composed of metal containing silver attachedthereto for cooperation with its associated contactor, and meanscomprising an insulatin cover member attached to said base and adaptedto retain all of said parts in assenbled position.

12. In an electric switch of the slow break type, in combination, amolded insulating base having a pair of side recesses and anintermediate recess alined with each other transversely of said basebetween opposite ends of the latter, each of said side recesses being ofinverted, stepped, substantially pyramidal form in vertical crosssection longitudinally of said base, a coiled compression spring havingits lower end seated in the lower or smallest portion of each siderecess, a bridging contactor of substantially U- shape having its armsand connecting portion positioned within the next larger portion of saidrecess and seated against the upper end of said spring, the ends of saidarms being bent to extend therefrom in opposite directionslongitudinally of said base for vertical movement within the upper orlargest portion of said recess, the side walls of said intermediaterecess having notches formed therein and extending throughout the majorportion of the depth thereof, a flat insulating member slidablypositioned within said notches, the opposite end portions of saidinsulating member being adapted to fit rather loosely between th arms ofthe respective contactors, said springs acting to bias said contactorsand said insulating member toward their upper extreme positions, twopairs of stationary contacts having portions thereof seated upon saidbase in a substantially flush relation to the upper surface of thelatter, the tips of each pair of contacts overlying the bent ends of thearms of one of said contactors, and an insulating cover member securedto the upper surface of said base and adapted to retain all of theaforementioned parts in assembled relation.

13.111 an electric switch of the slow break type, in combination, amolded insulating base having a pair of side recesses and anintermediate recess alined with each other transversely of said basebetween opposite ends of the latter, each of said side recesses being ofinverted, stepped, substantially pyramidal form in vertical crosssection longitudinally of said base, a coiled compression spring havingits lower end seated in the lower or smallest portion of each siderecess, a bridging contactor of substantially U- shape having its armsand connecting portion positioned within the next larger portion of saidrecess and seated against the upper end of said spring, the ends of saidarms being bent to extend therefrom in opposite directionslongitudinally of said base for vertical movement within the upper orlargest portion of said recess, a coiled compression spring positionedwithin said intermediate recess, the side walls of said intermediaterecess having notches formed therein and extending throughout the majorportion of the depth thereof, a flat insulating member slidablypositioned within said notches and seated against the upper end of saidlast mentioned spring, the opposite end portions of said insulatingmember being adapted to fit rather loosely between the arms of therespective contactors, said springs acting to bias said contactors andsaid insulating member toward their upper extreme positions, two pairsof stationary contacts having portions thereof seated upon said base ina substantially flush relation to the upper surface of the latter, thetips of each pair of contacts overlying the bent ends of the arms of oneof said contactc-rs, an insulating cover member secured to the uppersurface or said base and adapted to retain all of the aforementionedparts in assembled relation, and manually operable means for eifectingdownward movement of said insulating member and said contactors againstthe bias of said springs.

14. In an electric switch of the slow break type, in combination, amolded insulating base having a pair of side recesses and anintermediate recess alined with each other transversely of said basebetween opposite ends of the latter, each of said side recesses being ofinverted, stepped, substantially pyramidal form in vertical crosssection longitudinally of-saidbase, a coiled-compression spring havingits lower end seated in the lower or smallest portion of each siderecess, a-bridg ing contactor of substantially U-shapehavingits arms andconnecting portion positioned within the 'next larger portion of saidrecess and-seated against the=upper-endof said spring,'the endsofsaid-arms being'bent to extend therefromin opposite directionslongitudinally of said base for vertical movement within the upper-orlargest portion of said recess-the sidewalls of said intermediate recesshaving notches formed therein and extending throughout the major portionof the-depth thereof, a flat insulatingmember slidably positioned withinsaid notches, the= opposite end portions of said insulatingmemberbeingadapted to fit rather loosely between thearms of therespectivecontactors, said springs acting to bias said contactorsandsaid insulating member .toward their upper extreme positions, two pairsof stationary contacts having portions thereof seated 'upon said baseinasubstantially flush relation to the upper surface of-thelatter, the tipsof 4 each pair of contacts overlying the bent ends of the arms of one ofsaidcontactors, an insulating cover member secured tothe upper surfaceof said base and-adaptedto retain allof the aforementioned parts -inassembled relation,

andmanuallyoperable meansfor effecting downward movement ofsaidinsulatingmember and said contactorsagainst the biasof-said springs,said last mentioned means comprising an insulating cam member pivotallysupportedwithin said intermediate recess and alsoretained in assembledrelation by said insulating cover member.

15. In anelectricswitch of the slow breaktype, in combination, a moldedinsulatinglbaselhaving a pair of side recessesiandan intermediate recessalined with each other transversely of saidcbase between opposite endsof the latter, eachofzsaid side recesses being of inverted, stepped,substantially pyramidal form in vertical cross section longitudinally ofsaid base, a coiled compression spring'having'itslower 'endseated in thelower or 'smallestiportion of each side recess, a bridging contactor ofsubstantially U.-shape having its arms and connecting portion positionedwithin the .next larger portion .of said recess and seated against theupper end of said spring, the ends of said arms beingbent to extendtherefrom in opposite directions longitudinally of said base forvertical movement within the upper or largest portion of said recess,each of said contactors comprising a bimetallic strip bent flatwise tothe form defined, said'strip having ailayer of. metalcontaining copperand a layer of metal containing'silver, the arrangement being such thatsaid last mentioned layer of metal is exposedat the upper surfacesofisaid bent ends of the contactor arms, a relatively stronger coiledcompression spring being positioned within said intermediate recess,iafiat insulating member seated against said last mentioned spring andhaving end portions reciprocable with the respective side recesses, saidend portions being adapted to respectively fit between the arms of saidcontactors to assist'in guiding theilatter for movement in a straightline, two sets ofsheet metal contact members having portions thereofseatedflatwise upon'said base in a substantially flushirelation to theupper surface of the latter, each of said contact members having a tipportion of metal con-taining silver attached to the lower surfacethereof 'for cooperation withlits associatedcontacton-anda flat, punchedinsulating plate rigidly securedto the upper surface of said base andadapted to positively retain all of said parts in assembled relation.

16. In an electric switch ofthe slow-breaktype, in combination, amoldedinsulating base-having a a pairof side recesses and anintermediate recess alined with each other transversely of said basebetween oppcsite ends ofthe latter,each of said side recesses being ofinverted, stepped, substantially pyramidal form in vertical crosssectionlongitudinally of said base, acoiled compression sprin-g :havingits lower-end seated in the lower orsmallest portion of each siderecess, a bridging contactorof substantiallyU-shape having its arms andconnecting portion positioned within the-next larger'portionofsaidrecess and seated against theupper endcf said spring, the endsofsaid arms being bent to extend-therefrom in opposite directionslongitudinally of said base for vertical movement within the upper orlargestportion of said-recess, eachof said contactors comprising abimetallic'strip bent flatwiseto the form defined, said strip having alayer'ofmetal containing copper, and a layer of metal containingsilver,the arrangement being such that said last'mentioned'layer of metal isexposed atthe upper surfaces of said bent ends of the contactor arms, arelatively stronger coiled compression spring being positioned withinsaid intermediate recess, a fiat insulating member seated against saidlast-mentioned spring and having endportions reciproca-ble with therespective side recesses said end portions being adapted torespectively'fit between the arms of said contactors to assist inguiding the latter for movement in a straight line, two sets ofsheetmetal contact members having portions thereof seated flatwise uponsaid base in a substantially flush relation to the upper surface of thelatter, each of said contact members having 'a tip-portion-of metalcontainingsilver attached -to the lower surface thereof for cooperationwith its associated contactor, a flat, punched insulating plate rigidlysecured to the upper surface of said base and adapted to positivelyretain all of said parts in assembledrelation, and means comprising amovable member operable at will to eifect downward movement of saidinsulating member and said contactors against the bias of said springs.

17. In' an electric switch of the slow break type, in'combination, amolded insulating-base having a'pair of side recesses and anintermediate recess alined with each other transversely of said basebetween opposite'ends of the latter, each of said side recesses being ofinverted, stepped, substantiallypyramidal f'ormin'vertical cross sectionlongitudinally of said base, a coiled compression spring havingits-lowerend seated in the lower or smallest portion of each side recess, abridging contactor of substantially -U-shape having its arms andconnecting portion positioned within the next larger portion of saidrecess andseated against the upper end of said spring,'the ends of saidarms being bent to extend therefrom in opposite directionslongitudinally of said base for vertical movement Within the upper orlargest portion of said recess, each of said contactors comprising abimetallicstrip bent flatwise to the form defined, said strip having alayer of metal containing copper and a, layer of metal containingsilver, the arrangement being such that said last mentioned layer ofmetal is exposed at the upper surfaces of said bent ends of thecontactor arms, a flat insulating member having end portionsreciprocable with the respective side recesses, said end portions beingadapted to respectively fit between the arms of said contactors toassist in guiding the latter for movement in a straight line, two setsof sheet metal contact members having portions thereof seated flatwiseupon said base in a substantially flush relation to the upper surface ofthe latter, each of said contact members having a tip portion of metalcontaining silver attached to the lower surface thereof for cooperationwith its associated contactor, a flat, punched insulating plate rigidlysecured to the upper surface of said base and adapted to positivelyretain all of said parts in assembled relation, and means comprising amovable member operable at will to effect downward movement of saidinsulating member and said contactors against the bias of said springs,said last mentioned means including an insulating cam member pivotallysupported within said intermediate recess and also positively retainedin assembled relation by said insulating plate.

18. In an electric switch of the slow break type, in combination, amolded insulating base having a pair of side recesses and anintermediate recess alined with each other tranversely of said basebetween opposite ends of the latter, each of said I side recesses beingof inverted, stepped, substantially pyramidal form in vertical crosssection longitudinally of said base, a coiled compression spring havingits lower end seated in the lower or smallest portion of each siderecess, a bridging contactor of substantially U-shape having its armsand connecting portion positioned within the next larger portion of saidrecess and seated against the upper end of said spring, the ends of saidarms being bent to extend therefrom in opposite directionslongitudinally of said base for vertical movement within the upper orlargest portion of said recess, each of said contactors comprising abimetallic strip bent flatwise to the form defined, said strip having alayer of metal containing copper and a layer of metal containing silver,the arrangement being such that said last mentioned layer of metal isexposed at the upper surfaces of said bent ends of the contactor arms, arelatively stronger coiled compression spring positioned within saidintermediate recess, a fiat insulating member seated against said lastmentioned spring and having end portions reciprocable with therespective side recesses, said end portions being adapted torespectively fit between the arms of said contactors to assist inguiding the latter for movement in a straight line, two sets of sheetmetal contact members having portions thereof seating flatwise upon saidbase in a substantially flush relation to the upper surface of thelatter, each of said contact members having a tip portion of metalcontaining silver attached to the lower surface thereof for cooperationwith its associated contactor, a flat, punched insulating plate rigidlysecured to the upper surface of said base and adapted to positivelyretain all of said parts in assembled relation, means comprising amovable member operable at will to effect downward movement of saidinsulating member and said contactors against the bias of said springs,said last mentioned means including an insulating cam member pivotallysupported within said intermediate recess and also positively retainedin assembled relation by said insulating plate, and said last mentionedmeans also including means cooperable with said cam member to releasablyretain the latter, said insulating member and said contactors in theirlower extreme positions upon the aforementioned downward movementthereof.

19. In an electric switch of the slow break type, in combination, amolded insulating base having a pair of side recesses and anintermediate recess alined with each other transversely of said basebetween opposite ends of the latter, each of said side recesses being ofinverted, stepped, substantially pyramidal form in vertical crosssection long1tudinally of said base, a coiled compression spring havingits lower end seated in the lower or smallest portion of each siderecess, a bridging contactor of substantially U-shape having its armsand connecting portion positioned within the next larger portion of saidrecess and seated against the upper end of said spring, the ends of saidarms being bent to extend therefrom in opposite directionslongitudinally of said base for vertical movement within the upper orlargest portion of said recess, each of said contactors comprising abimetallic strip bent fiatwise to the form defined, said strip having alayer of metal containing copper and a layer of metal containing silver,the arrangement being such that said last mentioned layer of metal isexposed at the upper surfaces of said bent ends of the contactor arms, aflat insulating member having end portions reciprocable with therespective side recesses, said end portions being adapted torespectively fit between the arms of said contactors to assist inguiding the latter for movement in a straight line, two sets of sheetmetal contact members having portions thereof seated flatwise upon saidbase in a substantially flush relation to the upper surface of thelatter, each of said contact members having a tip portion of metalcontaining silver attached to the lower surface thereof for cooperationwith its associated contactor, a flat, punched insulating plate rigidlysecured to the upper surface of said base and adapted to positivelyretain all of said parts in assembled relation, means comprising amovable member operable at will to effect downward movement of saidinsulating member and said contactors against the bias of said springs,said last mentioned means including an insulating cam member pivotallysupported within said intermediate recess and also positively retainedin assembled relation by said insulating plate, said last mentionedmeans also including means cooperable with said cam member and tendingto normally releasably retain the latter, said insulating mem ber andsaid contactors in their lower extreme positions upon the aforementioneddownward movement thereof, and means comprising a single springassociated with said movable member and adapted upon manual release ofthe latter to bias all of said last mentioned parts to said lowerextreme positions against the action of said coiled compression springs.

20. In a single pole, single throw, four-break switch of the slow breaktype, in combination, a molded insulating base having a group of threetransversely alined parallel recesses formed therein and opening to theupper surface thereof, a substantially U-shaped contactor slidablymounted in each of the end recesses of said group, a coiled compressionspring interposed between the bottom wall of each end recessand itsassociated contactor thereby said contactors are normally biased towardtheir upper extreme positions, the adjacent walls of said recesseshaving vertical notches formed therein, a flat, punched insulating platepositioned edgewise within said notches and having end portions locatedbetween the arms of said contactors and overlying the connectingportions of the latter, a coiled compression spring interposed betweenthe bottom wall of the central recess and the lower edge of said plateto normally bias the latter toward its upper extreme position, a pair oflongitudinally spaced stationary contacts overlying the upper end ofeach of said end recesses for cooperation with the respectivecontactors, said contacts having portions thereof seated upon said basein a substantially flush relation and interlocked against transversemovement with respect thereto, two of the transversely alined contactsof said pairs having wiring terminal portions formed integrallytherewith and exposed at one end of said base, the other twotransversely alined contacts of said pairs having a bus portion formingan integral connection therebetween, said base having a transverselyextending groove formed in the upper surface thereof to accommodate saidbus portion, an insulating cam member oscillatably supported within saidcentral recess and adapted to overlie the upper edge of said :plate, anda flat, punched insulating plate rigidly secured to the upper surface ofsaid base to retain all of said parts in assembled relation.

21. In an electric switch of the slow-break type, in combination, amolded insulating base having a recess formed therein and opening to theupper surface thereof, substantially U-shaped contactors positionedwithin said recess, coiled compression springs interposed between thebottom wall of said recess and the connecting portions of the contactorsrespectively positioned therewithin whereby said contactors are normallybiased toward their upper extreme positions, a flat plate of insulatingmaterial reciprocable vertically within said recess, said plate beingpositioned between the arms of said contactors and adapted to seatagainst the connecting portions of the latter, the side walls of saidrecess cooperating with opposite ends of said plate to assist in guidingthe latter, manually operable means, including a cam member, carried bysaid base to provide for depression of said plate and said contactorsagainst the bias of said springs, a plurality of pairs of longitudinallyalined contacts positioned within said recess for bridging engagement bythe respective contactors in the upper extreme positions of the latter,the tips of said contacts being positioned in substantially flushrelation to the upper surface of said base, and a flat plate ofinsulating material secured to the upper surface of said base andadapted to overlie said contact tips and said contactors.

22. In an electric switch of the slow break type, in combination, amolded insulating base having a recess opening to the upper surfacethereof, said base having downwardly offset ledges formed thereon, apair of punched and stamped sheet metal contacts having portions seatedupon said ledges, the tips of said contacts being positioned in asubstantially flush relationship to the upper surface of said base,means to prevent substantial lateral displacement of said contactsrelatively to said base, the tips of said contacts overlying the upperend of said recess in spaced relationship to each other longitudinallyof said base, a substantially U-shaped contactor positioned within saidrecess, a coiled compression spring interposed between the bottom wallof said recess and said contactor to normally bias the latter intobridging engagement with said contact tips, a flat, punched insulatingplate positioned edgewise within said recess and having a portionoverlying the connecting portion of said U, and manually operable meansincluding a cam member movably supported by said base and overlying theupper edge of said plate, said cam member being movable at will toeffect depression of said plate and said contactor against the bias ofsaid spring.

23. In an electric switch of the slow break type, in combination, amolded insulating base having a pair of said recesses and anintermediate recess aligned with each other transversely of said basebetween opposite ends of the latter, a coiled compression spring havingits lower end seated in the lower portion of each side recess, abridging contactor of substantially U-shape having its arms andconnecting portion positioned within said recess and seated against theupper end of said spring, the ends of said arms being bent to extendtherefrom in opposite directions longitudinally of said base forvertical movement within the upper portion of said recess, the sidewalls of said intermediate recess having notches formed therein andextending throughout the major portion of the depth thereof, a flatinsulating member slidably positioned within said notches, the oppositeend portions of said insulating member being adapted to fit ratherloosely between the arms of the respective contactors, said springsacting to bias said contactors and said insulating member toward theirupper extreme positions, two pairs of stationary contacts carried bysaid base and having the tips thereof arranged in a substantially flushrelation to the upper surface of the base, the tips of each pair ofcontacts overlying the bent ends of the arms of one of said contactors,and an insulating cover member secured to the upper surface of saidbase, said cover having an opening formed therein to provide clearancefor an operating element of suitable form.

ALVIN W. KRIEGER.

